More than a few of the travelling supporters had O’Callaghan first to score at odds of 8/1, such was the anticipation surrounding his first game back in the Cork City colours.
And O’Callaghan was clearly eager to please. An ambitious back heel nearly cost him his hamstring in the 10th minute while he was first to offer himself for every set piece, enthusiasm which paid dividends after 16 minutes.
One of the areas the cup champions struggled last season was at the set piece but they may have remedied that by accepting back their controversial talent into the Leeside fold. His clever swinging strike from almost the left touchline snuck in at the near post, wrong-footing Dwayne Nelson.
Prior to that, there was an early set-piece chance for Dan Murray after he rose unmarked to meet O’Callaghan’s opening free but his glancing header went just wide. Another O’Callaghan free in the ninth minute went just over while Pat Sullivan, making his debut on the right side of midfield, had the first of a three shots on target in the 12th.
Occasional clumsiness from Cork could have allowed Dungannon back in. Darragh Ryan’s last ditch tackle stopped Dungannon striker Mark McAllister in the 15th minute and then, as the half-hour approached, Jamie Tomelty failed to profit from a mix-up at the back involving centre backs Dave Mulcahy and Murray, playing together for the first time, the Dungannon forward’s chip going straight to goalkeeper Michael Devine.
Either side of that chance, Dave Mooney had decent opportunities as he and Denis Behan began to gel.
And in the 40th, O’Callaghan was put through by a lofted Joe Gamble ball and despite being on his weaker left foot, he finished low under Nelson’s body.
Significantly, as referee Alan Black prepared to blow for half-time Liam Kearney fired another Cork free just over the bar.
The little winger created the second half’s opening chance when floating a set piece to Murray at the back post while Kearney was again involved when O’Callaghan and then Mooney failed to finish off a nice Cork move on 49 minutes.
Nelson denied Behan a minute later before the Cork striker hit the side netting in the 52nd minute after a clever flick into space from Mooney, leaving the debutant angered at not having received a return pass when in acres of space. The game got scrappy but man-of-the-match O’Callaghan was still piecing together Cork’s more progressive moves, notching down another clever effort in the 69th minute, an attempted lob of Nelson that went just over.
He was however reluctant at times to track back into his central role, a habit that may need amending.
Dave Mooney’s last action before being subbed for John O’Flynn was to strike the crossbar in the 90th minute, Kearney’s miss on the second ball was poor. It was blown up early but a combination of Cork dominance and the game struggling to revitalise meant that whistling a bit too soon was merciful of the Antrim official.
DUNGANNON SWIFTS (4-4-2): D Nelson; M McConkey (S Cunningham, 87), J Montgomery, J Curran, JP Gallagher (capt); A Friel, A McCarron, M Hegarty, D Murphy (S McGerrigan, 87); M McAllister (S Ferry, 84), J Tomelty.
CORK CITY (4-4-2): M Devine; C Lordan, D Mulcahy, D Murray (capt), D Ryan; P Sullivan, G O’Callaghan, J Gamble, L Kearney; D Behan, D Mooney (J O’Flynn, 90).
Referee: Alan Black (Antrim).